Friday, June 6, 2008

Landscape - Controlling Saplings

I was asked yesterday the best way to control saplings in a landscape bed. The following is some information on the subject of dealing with escaped or unwanted trees in landscapes.

Often in neglected landscapes, trees will come up from seeds in beds, hedges, or around foundations near the house. I may not be possible to dig the roots out without damaging the shrubs or perennials. The question then is how to kill the trees?

It is better to pull tree seedlings as small saplings, but sometimes they get large before we decide to intervene, or we get the contract on a property with the oversized woody weeds already well established.

In some cases, just cutting the tree as close to the ground as possible will be sufficient to kill the tree. If the tree is young, or a species that forms sprouts from the stump, you may find it necessary to weed out the sprouts for a year or two. That is, cut or pull the sprouts as soon as they develop, and don't allow them to become large. By removing the sprouts as they form, you prevent them from developing enough to begin storing food reserves in the roots (feeding the roots). Each time the sprouts form, food reserves must be withdrawn from the roots. By allowing withdrawals but preventing deposits in this food bank in the roots, you will bankrupt the root system and it will die.

Some trees will produce sprouts in the lawn. These sprouts develop from the roots. Again, removal of the sprouts to bankrupt the root system will eliminate the problem in time. It may take a while, but will be effective. If the original tree remains standing, however, sprouts will continue to be formed.

To hasten the bankruptcy of the root system, you may choose to use chemicals which translocate into the roots killing them. This process may not kill all the roots, but should kill more than the simple removal of trunk or root sprouts, speeding the demise of the roots. There are several products which may be used and are labeled for this purpose. They are called brush and stump killers and are based on growth regulator type herbicides. Some other herbicides, such as glyphosate are also labeled for this purpose.

It is possible, often preferable, to use these products while the tree is still standing so that the tree itself may assist in moving the product into the root system. Once the tree is cut, downward movement from the leaves to the roots is eliminated, and movement from the trunk to the roots is minimal. Applying the herbicides according to directions, while the tree remains standing, allows maximum effectiveness of the product. Some of these may be applied as applications to notches cut shallowly through the bark. You can mechanically damage the saplings (using a bush knife or machete) and then apply the herbicide and this will speed up the process. Application of products to freshly cut stumps works on many species.

Once a tree has been killed, or if it is cut while still living, use caution. If the tree is near a home or other structure, it may be wise to hire an insured, or bonded, tree care professional to minimize the likelihood of damage to the structure. You may be able to remove smaller trees yourself, but remember that even a small tree will be surprisingly heavy and can harm you or the structure. If the tree is killed before removing it, don't leave it standing a long time if it is near traffic ways or structures. The dead tree will fall in time and can do damage. You should remove it or have it removed so that it will fall in a manner that will do no damage.

Adapted from "Removing large tree saplings near foundation and in hedges" from New Mexico State University Extension.

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